Each target sheet has a series of 5 RAD Coded Targets, like this:
The calibration will work with 6 to 12 (or more) sheets (30-60 or more unique targets) in your space, provided that there is enough overlap between photos so that the majority of targets are visible in all or most photos.
You do not need to place the targets in any particular order – just print and spread the sheets around randomly. It is important to get sheets right to the outside of the area that will be photographed. Placing some sheets on a raised or angled plane will help provide a 3D configuration which can sometimes improve a calibration.
Note: Make sure that you do not duplicate a sheet in the calibration scene as this will cause trouble when calibration processing.